1. Field of the Invention
This invention relates to a substituted tetraphenylporphyrin silicon complex, polysiloxane, polysilane, a liquid crystal material, a photoconducting element, and a photo-functional charge-transfer material.
2. Description of the Prior Art
Heretofore, as respects the utility of a liquid crystal in the state intermediate state between solid and liquid in applications other than display element, some studies have been under way concerning the liquid crystal property and the photoconductivity of a discotic metal complex as a liquid crystal material of a new type altogether different in terms of molecular form from the conventional rodlike liquid crystal. The discotic liquid crystal as an electrically conductive material is characterized by manifesting a structure convenient for the transportation of holes or electrons (a columnar structure having disklike molecules stacked to produce a column) in the state of liquid crystal. Many materials have been known to allow satisfactory transportation of holes, whereas not many materials have been known to provide satisfactory transportation for electrons.
The present inventor has discovered for the first time that a novel porphyrin silicon complex exhibits a columnar lamellar liquid crystal phase and, on exposure to light on the surface of an ITO electrode, emits electron and constitutes a material for transporting electrons.
He has further discovered that the combination of this porphyrin silicon complex with a hole transporting agent promises development of a novel high-performance photo-function charge-transfer material (for example, an organic electroluminescent (EL) material).
An object of this invention, therefore, is to disclose an electron transferring material formed by a novel porphyrin silicon complex and teach a use thereof as a photo-functional charge-transfer material.
As a material conforming to this object, this invention contemplates a substituted tetraphenylporphyrin silicon complex represented by the following general formula (I): 
wherein R1, R2, R3, R4, and R5 independently denote a hydrogen atom, an alkyl group, an alkoxy group, or a polyalkyleneoxygroup, providing that the case in which R1-R5 invariably denote a hydrogen atom is excluded, and X and Y independently denote a hydroxyl group, an alkoxy group of C1-C3, or a halogen atom.
The complex satisfies the general formula (1) by having R1, R2, R4, and R5 invariably denote a hydrogen atom, R3 denote an alkyl group of 6-24 carbon atoms, and X and Y invariably denote an OH.
This invention further concerns a substituted tetraphenylporphyrin-containing polysiloxane containing a repeating unit represented by the general formula (II): 
wherein R1, R2, R3, R4, and R5 independently denote a hydrogen atom, an alkyl group, an alkoxy group, or a polyalkyleneoxygroup, providing that the case in which R1-R5 invariably denote a hydrogen atom is excluded and a siloxane type repeating unit as an arbitrary repeating unit.
This polysiloxane satisfies the general formula (II) by having R1, R2, R4, and R5 invariably denote a hydrogen atom and R3 denote an alkyl group of not less than six carbon atoms.
This polysiloxane has a siloxane type repeating unit denoted by Si(xe2x80x94Oxe2x80x94)4, Rxe2x80x94Si(xe2x80x94Oxe2x80x94)3, or R2Si(xe2x80x94Oxe2x80x94)2 {wherein R denotes methyl, ethyl, n-propyl, or isopropyl}.
This invention further concerns a substituted tetraphenylporphyrin-containing polysilane comprising repeating units represented by the general formula (III): 
wherein R1, R2, R3, R4, and R5 independently denote a hydrogen atom, an alkyl group, an alkoxy group, or a polyalkyleneoxy group, providing that the case in which R1-R5 invariably denote a hydrogen atom is excludes.
The polysilane satisfies the general formula (III) by having R1, R2, R4, and R5 invariably denote a hydrogen atom and R3 denote an alkyl group of not less than six carbon atoms.
This invention further concerns a liquid crystal material comprising the substituted tetraphenylporphyrin silicon complex mentioned above and a liquid crystal material possessing a columnar lamellar phase.
This invention materializes a photoconducting element by forming on an electrode a film containing the substituted tetraphenylporphyrin silicon complex or the polysiloxane or the polysilane mentioned above.
The photoconducting element having ITO for the electrode is particularly important from the practical point of view.
Further, a photo-functional charge-transfer material is composed of the substituted tetraphenylporphryin silicon complex mentioned above and a hole transporting agent.
The photo-functional charge-transfer material is allowed to use a charge-transfer material for the purpose of serving as an organic EL element or a solid electrolyte.